University of California Cooperative Extension The Pomology Post. Madera County Volume 48, MARCH 2005

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1 University of California Cooperative Extension The Pomology Post Madera County Volume 48, MARCH 2005 Red Imported Fire Ant Still in Madera County by Brent Holtz, Ph.D., UCCE Madera County times of drought. They also have been know to chew through irrigation lines to reach water. RIFA is also attracted to electrical fields around bare wire; once they contact the wire they are killed, but not before setting off an alarm pheromone that attracts other which can cause them to mass on the wire and ultimately cause the equipment to short out. Red Imported Fire Ant (RIFA) was found in 2000 on 742 acres of agricultural land that encompassed seven properties in Madera County. The California Department of Food and Agriculture initiated ant bait treatment program on these properties aimed at eradicating RIFA. In 2004, 395 acres remained under treatment. In the last five years over 50,000 acres of almonds have been surveyed in Madera County for RIFA. In November 2004, CDFA discovered new acreage infested with RIFA in Madera County, increasing the treatment area to about 1,300 acres. The CDFA, in conjunction with the Madera County Agricultural Commissioner, is in the process of developing a multi-year action plan to eradicate the infestation. RIFA was probably introduced into Madera County on infested beehives arriving from the southeastern United States used for pollination. The red imported fire ant (RIFA) is unique among exotic pests since it may impact so many facets of the state s population and economy. RIFA poses a threat to agriculture, to urban and suburban lifestyles, and to many California ecosystems. RIFA is a pest because of its sting to humans, its direct damage to crops and livestock, its interference with electrical and irrigation equipment, and its ability to misplace native species of ants. Red imported fire ants have been found to actually plug up irrigation systems when they need to find water in RIFA can also inflict damage to ground nesting birds and mammals. Immobilized animals such as penned livestock or young newborns and hatchlings are at greatest risk since RIFA are attracted to there mucus membranes causing blindness and potential suffocation. Animals which have learned to avoid RIFA may become malnourished or dehydrated when the ants have infested their food or water. The red imported fire ants arrival in the US occurred around 1940, probably on infested soil used as ballast on ships coming from South America. It is native to lowland areas of Argentina and Brazil. From its introduction point in Alabama it has spread outward at rates of over 100 miles per year. Its current geographic distribution includes the entire south from Florida to California and as far north as Virginia, Tennessee, and Oklahoma. The life cycle of a fire ant colony begins with a newlymated queen searching for a suitable next site in soil. During this search the queen is most vulnerable predators such as their mortal enemies, the Argentine ant. The Argentine ant and the red imported fire ant, both exotic pest ants from South America, are mortal enemies and fight to the death on contact. If the queen is lucky, she survives and finds a suitable next site where she snaps off her wings, burrows in the ground and seals herself off rom the outside to lay her first batch of eggs. University of California, U.S. Department of Agriculture and Madera County cooperating

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3 THE DIRT ON RED IMPORTED FIRE ANTS Recent Finds in Central San Joaquin Valley, by Arthur Gilbert, Entomologist, CDFA Recently discovered in Fresno County, Red Imported Fire Ants are tiny, but their aggressive nature has the potential to destroy farmland, injure agricultural workers, and kill livestock and wildlife. The California Department of Food and Agriculture (CDFA), in partnership with county agricultural commissioners, is waging war on the Red Imported Fire Ant with the goal of complete eradication. Below are answers to some frequently asked questions important to all Central Valley growers. What Do Red Imported Fire Ants look like? How are they different from other types of ants? Red Imported Fire Ants are tiny, measuring 1/16 to 1/4 of an inch in length, and are reddish-brown in color. They closely resemble other ants commonly found in California and can only be positively identified using a powerful microscope. However, they do have distinctive mounds and are aggressive in nature. In other parts of the country, their mounds resemble gopher mounds, with crumbly soil piled up to 18 inches high. But in California, the mounds tend to be small piles of powdery dirt with visible ant holes or are just flat patches of soil. Why are they dangerous to people? To crops? When Red Imported Fire Ants attack, hundreds of ants swarm and inflict painful stings that leave blister-like sores that could become infected if not treated carefully. Some people are allergic to fire ant venom, and if stung can experience difficulty breathing and other life threatening reactions. In addition, Red Imported Fire Ants can aggressively expand their colonies by feeding on crops and disrupting growers integrated pest management programs by eliminating beneficial insects. Any intruder to the nest is attacked by a swarm of ants which could prove life threatening to wildlife, animals and people. Young animals are especially susceptible. How did these ants make their way to California? Red Imported Fire Ants are believed to have first come to this country in the 1930s from South America aboard cargo ships that docked in Mobile, Alabama. Today, the pest has become endemic in a dozen southeastern states, inflicting harm to people, commerce and the environment. These pests were first discovered in California in the late 1990s. Since then, Red Imported Fire Ants have been reported in eight California counties including Los Angeles, Orange, Riverside and, in the Central Valley, Stanislaus, Madera, Kern and Fresno. It is suspected that Red Imported Fire Ant hitchhike on out-ofstate beehives brought into Fresno County. Specifically where in Fresno County have these ants been found? The first Red Imported Fire Ant discovery in the San Joaquin Valley was found in an almond orchard. After that, Red Imported Fire Ant infestations have been reported and confirmed in various areas throughout Fresno County including Clovis and Kerman. The Pomology Post Page 3

4 Where are Red Imported Fire Ants typically found? Red Imported Fire Ants have been found in agricultural areas, such as irrigation ditches, the bases of trees, beehive staging areas, orchard perimeters and electrical areas, like irrigation pump houses. Red imported Fire Ant mounds are most commonly found in almond orchards and crops that use honeybees. However, neighboring fields also can be at risk since Red Imported Fire Ant queens can establish new colonies hundreds of feet away from their previous colonies. How can farmers and gardeners protect themselves against these ants? Stay alert! Farmers and gardeners should wear protective clothing including gloves and close-toed shoes when outdoors - especially when Red Imported Fire Ants are most active, when temperatures reach between degrees. Be careful where you walk or dig; survey the area first. Also, if you re stung, remember to keep the area clean by washing with soap and warm water and resist scratching to avoid possible infection. Applying ice or an antihistamine ointment may help to relieve the pain and itching. Seek medical attention immediately if signs of allergic reaction appear, such as severe swelling, shortness of breath, dizziness, nausea, headaches or profuse sweating. What are typical Red Imported Fire Ant warnings signs for farmers and gardeners? If farmers and gardeners answer yes to any of the following questions, they should contact their county agricultural commissioner s office for a free inspection of their property: Have you, or your neighbor, ever used bee colonies that originated from Texas, Louisiana or any other state infested with Red Imported Fire Ants? Do the beehives or their pallets show evidence of packed dirt? Are there any clumps of packed dirt in the bed of the beekeeper s delivery truck? Does the bee colony appear weak or dead? Have you or your workers encountered unusually aggressive ants. What should a farmer or gardener do if a Red Imported Fire Ant mound is found or suspected? Do not disturb the suspected mound or nest, and don t try to kill the ants or destroy the nest yourself! If you suspect you have found a Red Imported Fire Ant mound on your property, call the California Department of Food and Agriculture s toll-free hotline at FIREANT. Your property will be inspected and treated free of charge. Can Red Imported Fire Ants be eradicated from agricultural lands? Completely eradicating Red Imported Fire Ants from this area will take the cooperation of all residents. Calling and reporting any suspected find is the best and most important first step in eradicating Red Imported Fire Ants. Keep the toll-free number handy, FIREANTS, and tell others to do the same to help eradicate Red Imported Fire Ants from California. More information can be found at the CDFA website which can be accessed through malcolmnmedia.com. The Pomology Post Page 4

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6 For special assistance regarding our programs, please contact us. Reprint freely with credit to: Brent A. Holtz, Ph.D., Pomology Farm Advisor, University of California Cooperative Extension, Madera, CA. Sincerely, Brent A. Holtz, Ph.D. Pomology Farm Advisor The University of California prohibits discrimination or harassment of any person on the basis of race, color, national origin, religion, sex, gender identity, pregnancy (including childbirth, and medical conditions related to pregnancy or childbirth), physical or mental disability, medical condition (cancer-related or genetic characteristics), ancestry, marital status, age, sexual orientation, citizenship, or status as a covered veteran (covered veterans are special disabled veterans, recently separated veterans, Vietnam era veterans, or any other veterans who served on active duty during a war or in a campaign or expedition for which a campaign badge has been authorized) in any of its programs or activities. University policy is intended to be consistent with the provisions of applicable State and Federal laws. Inquiries regarding the University s nondiscrimination policies may be directed to the Affirmative Action/Staff Personnel Services Director, University of California, Agriculture and Natural Resources, 300 Lakeside Drive, 6 th Floor, Oakland, CA , (510) UNIVERSITY OF CALIFORNIA NON PROFIT ORG COOPERATIVE EXTENSION US POSTAGE MADERA COUNTY PAID 328 MADERA AVENUE PERMIT NO. 13 MADERA CA MADERA CA The Pomology Post

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